PURPOSES : This study investigates the effects of three different three-color arrow traffic light operations on right-turn vehicles at intersections in Busan Metropolitan City. METHODS : Intersections in this study were categorized as general intersections (Type 1), intersections with right-turn pockets (Type 2), and intersections with scramble crosswalks (Type 3), and were investigated in terms of the efficiency (i.e., control delay) and safety (i.e., number of conflicts) of right-turn vehicles by employing VISSIM 2023 and SSAM3. RESULTS : From a mobility perspective (i.e., control delay), the protected/permitted operation outperformed the other two methods at the three types of intersections. The protected operation, similar to the results of the protected/permitted operation, was also superior to the permitted operation in terms of safety (i.e., number of conflicts). CONCLUSIONS : Protected/permitted operation has been proven to be a more efficient and safer measure than other operation methods for alleviating the problems of protected right-turn operation, which is currently implemented without three-color arrow traffic lights.

PURPOSES : This study aims to evaluate the traffic safety by collecting and analyzing vehicle speed and conflict frequency data based on the provision of information to vehicle drivers and crosswalk pedestrians under right-turn conditions. METHODS : Two evaluation scales, namely speed of access and number of conflicts, were used to quantitatively evaluate the effects of the new information provision method. Data on access speed and the number of conflicts according to information provision were collected and compared before and after information provision. RESULTS : Analysis of the pre- and post-spot speed reduction rates revealed an overall reduction rate of 32.6%. The conflict ratio was 81.0% before information provision but increased to 83.3% after information provision. CONCLUSIONS : When LED display information was provided, the effect of decelerating the approaching speed of vehicles in the rightturn torpedo section was statistically significant, but the reduction in the conflict ratio was not. Factors such as intersection status, traffic volume and vehicle speed, affect the approach speed and increase or decrease the number of conflicts. Regardless of whether information is provided, the average compliance rate of the Road Traffic Act when turning right in the channelization area is 16.7%, which is significantly different from the average compliance rate of 48.4% immediately after the Road Traffic Act was revised in July 2022.

PURPOSES : In this study, we review the method and equations suggested in the usual guidelines to calculate the lane widening for curved sections, and proposed values of the widths and the amount of widening that reflected the driving trajectory of an articulated bus. METHODS : A simulation was used to obtain the trajectory of articulated bus, which is adequate for a Super-Bus Rapid Transit(S-BRT) service with the longest length of the design vehicle. This study was conducted by dividing the trajectory into curved and tangential sections, and the extent of widening was analyzed by changing the rotation angle by 5°. In addition, the results related to the amount of widening from the conducted analysis were applied to particular situation of right turns of an articulated bus at urban intersection. The possible conflict situations that may occur were analyzed. RESULTS : When analyzing the rotation angle at which the size of the driving width was set to be the largest for each lane center radius, the rotation angle for a lane center radius ( =15m) was 35°, the rotation angle for a lane center radius ( =20m) was 45°, the rotation angle for a lane center radius ( =25m) was 55°, and the rotation angle for a lane center radius ( =30m) was 60°. CONCLUSIONS : As the radius increases, the required driving width and the amount of widening decrease. The rotation angle that requires the largest driving width is presented. The results show that as the central radius ( ) of the lane increases, the amount of widening for each rotation angle decreases. In addition, based on the results of the analysis of the driving width for each rotation, the trajectory of an articulated bus was applied to an at-grade intersection to check the distance required for widening from the beginning point of the curve.

PURPOSES : The purpose of this study is to establish design criteria for right-turning lanes by analyzing the relationship between the speed and geometry of right-turning lanes in urban areas. METHODS : A right-turn vehicle with a traffic island was surveyed for 32 geometries and 4,012 vehicles. Using multiple regression, we developed a running speed prediction model based on the running speed characteristics and geometry scale. RESULTS : According to the analysis of the running speed of the right-turning channel, the 85th speed was 34.5-38.3 km/h, depending on the right-turning lane radius, and 32.4-39.0 km/h, depending on the channel width group. Based on the multi-regression, the right-turning radius and the channel width variables were statistically significant because of the influencing factors of the road speed. Two independent variables were positive (+) coefficients. CONCLUSIONS : In this study, we investigated the running speed state on the right-turning channel and the factors that influenced the running speed. In addition, the relationship between the running speed and other factors was modeled through statistical analysis, and a running speed prediction model was established. It was observed that the driving speed increased as the geometry scale increased. Based on the derived running speed model, the maximum design criteria for limiting the speed of the conductive channelized right-turning lane in urban areas were established.

PURPOSES: The objective of this study is to establish the traffic volume-based warrants of right-turn lanes at unsignalized intersections and to introduce a risk probability methodology based on the warrants.METHODS : In this study, a risk probability of a potential rear-end collision is applied between a right-turn vehicle and the immediately following through vehicle. Using the shifted negative exponential model and the compound probability theorem, the risk probability can be expressed as the function of directional volumes and the percentage of right-turns for a two-lane and four-lane highway, respectively.RESULTS : Based on the risk probablity, guidelines for installing right-turn lanes on two-lane and four-lane highways were developed. The risk probability also showed rationality by comparing with right-turn same-direction conflicts observed in-situ.CONCLUSIONS : The results of our study define the total approaching volumes to encourage a right-turn lane as a function of operating speed, percentage of right-turn, and number of lanes.

신호교차로의 우회전 차로의 현 대기차량 길이 산정은     × × 과 같이 적용한다. 여기서, 길이계수 값(⍺)은 2.0이며 ‘lane overflow’가 일어날 확률이 대략 99%에 해당된다. N는 우회전 자동차의 수(신호 1주기당 도착하는 우회전 자동차)이며 S(m)는 대기하는 자동차의 길이이다. 그러나 이 방식은 도착하는 우회전 자동차의 수만을 기반으로 산정하며 대기차량 대수에 영향을 주는 다른 요인들(예를들면, 접근 교통량, 적색 신호시 우회전 가능 조건, 신호현시 조건 등)을 고려하지 않았다. 특히, 신호교차로에서 자주 발생하는 ‘lane blockage’현상을 고려하지 않았다는 점이다. 이로 인해 다양한 도로·교통 조건에서 현 대기차량 길이가 과대 혹은 과소평가 문제가 잠재적으로 존재한다고 판단된다. 이를 위해 Kikuchi와 Kronprasert 모델을 적용하여 우리나라의 도로·교통여건(신호운영 조건 포함)에 대응하는 신호교차로의 우회전 전용차로 길이를 산정하였다. Kikuchi와 Kronprasert 모델에 대해 신호교차로 접근로에서 4가지 대기패턴이 일어날 확률 계산과정은 다음과 같다. 첫 번째 단계는 적색 신호현시가 종료되는 시점에서 4개의 차량 대기 패턴(① ‘overflow’와 ‘blockage’현상이 발생하지 않는 조건, ② ‘blockage’현상이 발생할 조건과 그렇지 않는 조건, ③ ‘overflow’현상이 발생할 조건과 그렇지 않는 조건, ④ ‘overflow’와 ‘blockage’현상 발생하는 조건) 규명이다. 두 번째 단계는 각 차량 대기 패턴 경우별 확률 계산이다. 직진과 우회전 차량의 도착률과 허용 대기공간의 함수로서 각 패턴에 대한 확률 유도하며 적색현시동안 우회전이 가능하기 때문에 적색신호시 우회전 가능한 대수도 함수의 변수로 반영된다. 예를들면, 각 직진/우회전(i, j) 차량이 도착시 대기 패턴의 경우에 대한 확률은 다음과 같이 산정한다.          와  차량 도착 ×       와  차량 도착                     ,              여기서, i = 적색현시동안 도착하는 직진차량 대수, k = 적색현시동안 도착하는 우회전차량 대수 C = 우회전 차로의 허용 대기 길이(대수), = 적색현시당 차로당 도착하는 평균 직진차량 대수  = 적색현시당 차로당 도착하는 평균 우회전차량 대수 NR = 적색현시시 최대 우회전 가능한 대수, vc = 상충 교통량(대/시/차로) g/C = 유효 녹색시간비, tc = 임계간격수락(초), tf = 추종시간(초) 최종적으로 각 대기 패턴의 경우에 대한 확률값을 토대로                          ≥  혹은                    ≤   와 같이 우회전 전용차로의 길이를 산정한다. 여기서, ⍺ = ‘overflow’ 혹은 ‘blockage’가 발생하지 않을 확률 0.95이다. <그림 1>는 신호주기 90초와 유효녹색시간비(g/C)가 0.3에 대한 7개 ‘lane overflow’와 ‘lane blockage’ 현상에 대한 확률분포를 보여주고 있다. 이러한 각 도로·교통 조건별로 확률분포도를 산정하여 신호주기 90초, 120, 150초별, 직진 교통량과 우회전 교통량 관계를 기반으로 우회전 대기 차량 대수를 기 방식과 비교·평가하였다.

PURPOSES: This study is to develop Right-Turning Channelization Design Models of Semitrailer at Intersections by regression of vehicle tracking simulation. METHODS: Based on the literature review, it was indicated that right-turning channelization design guide of semitrailer is too complex and is not reflected turning speed and approach angle. To verify effectiveness of right turning semitrailer trajectories according to the changing turning speed and approach angle, vehicle tracking simulation was executed. And then, simulation results were analyzed for modeling design elements; minimum turning radius, swept path width, arc length, width of triangle island, of right-turning channelization using regression methods. RESULTS : When the turning speed is getting higher, minimum turning radius, arc length, width of triangle island increased and the approach angle lower, swept path width, arc length, width of triangle island reduced. The turning radius completely reflected by turning speed. CONCLUSIONS : In this research, it was investigated how much design elements are changed according to the turning speed and the approach angle of semitrailer. The developed right-turning channelization design models can help engineers to easy and comfortable design at various conditions.

이 논문은 회전교차로 우회전 별도차로를 다루고 있다. 본 연구의 목적은 회전교차로 기하구조의 설계요소 중 우회전 별도차로의 설치에 따른 효과를 분석하는데 있다. 이를 위해 VISSIM을 이용하여 우회전 별도차로의 설치 전 후를 비교 분석하였다. 또한 우회전 별도차로 설치 방식인 양보에 의한 통제 형태와 합류에 의한 통제 형태의 운영효과를 비교 분석하였다. 주요 결과는 다음과 같다. 첫째, 우회전 별도차로 설치 후에는 우회전 교통량비의 증가에 따라 지체가 점차적으로 감소하여 최대 평균 약 28% 감소하는 것으로 나타났다. 둘째, 양보에 의한 통제 형태와 합류에 의한 통제 형태 모두 우회전 교통량이 증가할수록 지체가 감소하였다. 또한 합류에 의한 통제 형태가 양보에 의한 통제 형태보다 최대 평균 약 18% 지체감소 효율이 있는 것으로 나타났다.